scholarly journals Evaluation of Astringency and Umami of Green Tea Infusions with Different Elution Conditions Using a Taste Sensor System

2014 ◽  
Vol 61 (5) ◽  
pp. 192-198 ◽  
Author(s):  
Tomoko Kubo ◽  
Takayuki Fujiwara ◽  
Yoshiko Tomizawa
Keyword(s):  
Green Tea ◽  
Sensor System ◽  
Tea Infusions ◽  
Taste Sensor

scholarly journals Deviation in Astringent and Umami Taste Intensity Values of Leaf-type Green Tea Using Taste Sensor System in Interlaboratory Trial

2017 ◽  
Vol 64 (2) ◽  
pp. 74-80
Author(s):  
Tomomi Ujihara ◽  
Nobuyuki Hayashi ◽  
Ronggang Chen ◽  
Masaaki Habara ◽  
Hidekazu Ikezaki
Keyword(s):  
Green Tea ◽  
Sensor System ◽  
Taste Intensity ◽  
Leaf Type ◽  
Umami Taste ◽  
Interlaboratory Trial ◽  
Taste Sensor

Techniques for Universal Evaluation of Astringency of Green Tea Infusion by the Use of a Taste Sensor System

2006 ◽  
Vol 70 (3) ◽  
pp. 626-631 ◽  
Author(s):  
Nobuyuki HAYASHI ◽  
Ronggang CHEN ◽  
Hidekazu IKEZAKI ◽  
Shinya YAMAGUCHI ◽  
Daisuke MARUYAMA ◽  
...  
Keyword(s):  
Green Tea ◽  
Sensor System ◽  
Tea Infusion ◽  
Taste Sensor

Dissipation, Processing, Leaching, and Safety Evaluation of Flonicamid and Its Metabolites in Tea

2020 ◽  
Vol 103 (6) ◽  
pp. 1441-1450
Author(s):  
Ya Yang ◽  
Xiangwu Liu ◽  
Qingtao Zhang ◽  
Ya Chen ◽  
Sumei Zhang ◽  
...  
Keyword(s):  
Green Tea ◽  
High Performance ◽  
Alcoholic Beverage ◽  
Safety Evaluation ◽  
Tea Infusions ◽  
Relative Standard ◽  
Liquid Chromatography Tandem Mass ◽  
Chinese Consumer ◽  
Transfer Behavior ◽  
Single Factor Analysis

Abstract Background Tea is a popular traditional non-alcoholic beverage worldwide. Flonicamid is a selective systemic pyridine carboxamide insecticide that is widely used for controlling tea leafhopper in tea. Objective The leaching rates, dissipation dynamics, and residue levels of flonicamid and its metabolites in tea leaves during processing and transferring were investigated to validate the safe risk in tea and transfer behavior using high performance liquid chromatography–tandem mass spectrometry with a convenient pretreatment method. Method The extracting method and immersion rate experiments were optimized by single factor analysis and orthogonal tests. The acetonitrile extracting solvent with 0.5% formic acid was used and optimal leaching conditions were obtained with a regime of 15 min immersion time, 100°C temperature, three immersions and a tea-to-water ratio of 1:50. Results Average recoveries in processed green tea and infusions were 80.85–98.75% with relative standard deviations <5.87%. LODs and LOQs of flonicamid, 4-trifluoromethylnicotinic acid (TFNA), N-(4-trifluoromethylnicotinoyl) glycine (TFNG), and 4-trifluoromethylnicotinamide (TFNA-AM) were 0.0013–0.350 and 0.004–1 μg/g, respectively. The processing factor of flonicamid was 0.36–5.52 during green tea manufacture. The leaching rates were 22.9-97.4% from processed tea to infusion. Conclusions The risk of long-term and short-term dietary intake of flonicamid was safe in tea infusions with the risk quotient (RQ) values <1 for the Chinese consumer. This work may provide guidance for safe and reasonable consumption of flonicamid in tea in China. Highlights The suitable leaching factors of flonicamid and its metabolites in tea infusions were optimized by orthogonal experimentation for the first time.

scholarly journals Green Tea Daily Consume Reduced Free Radicals on Moderate Smokers

2018 ◽  
Vol 2 (2) ◽  
pp. 39
Author(s):  
Rosyanne Kushargina ◽  
Rimbawan Rimbawan ◽  
Budi Setiawan
Keyword(s):  
Free Radicals ◽  
Experimental Design ◽  
Antioxidant Capacity ◽  
Green Tea ◽  
Black Tea ◽  
Intervention Period ◽  
Tea Leaves ◽  
Positive Effects ◽  
Tea Infusions ◽  
Total Antioxidant

<p><em>Smoking </em><em>can </em><em>enhance </em><em>free radicals on blood plasma. Many previous studies proved that tea is a source of antioxidants which might reduce free radicals. Green tea is known to have the higher antioxidant capacity compared to </em><em>black tea</em><em>.</em><em> This study aim</em><em>s </em><em>to analyze the effect </em><em>of green tea on reduction of free radicals on moderate smokers</em><em>, using a pre-post experimental design. </em><em>Green tea infusions were prepared with commercially available dried tea leaves (Green Tea Gamboeng Series) from the </em><em>Research</em><em> </em><em>Centers of Tea</em><em> </em><em>and</em><em> </em><em>Cinchona</em><em> Gambung, West Java. </em><em>Nine moderate smokers (11-21 cig/day) aged 30-45 years were instructed to drink 200 ml green tea three times a day for </em><em>four</em><em> weeks. Total Antioxidant Capacity (TAC) of blood serum was measured at baseline and after four weeks intervention period. The level of TAC significantly increased from 1.18 m mol/L to 1.34 m mol/L after </em><em>four</em><em> weeks intervention (P=0.000). These results prove that drinking 200 ml of green tea </em><em>three</em><em> times a day for </em><em>four</em><em> weeks has a significant benefit reduc</em><em>ing f</em><em>ree radicals of moderate smokers. Moderate smokers are advised to consume green tea continuously to sustain these positive effects.</em><em></em></p>

scholarly journals Effects of different brewing conditions on catechin content and sensory acceptance in Turkish green tea infusions

2015 ◽  
Vol 52 (10) ◽  
pp. 6639-6646 ◽  
Author(s):  
Sena Saklar ◽  
Erdal Ertas ◽  
Ibrahim S. Ozdemir ◽  
Bulent Karadeniz
Keyword(s):  
Green Tea ◽  
Sensory Acceptance ◽  
Tea Infusions

Screening of the antioxidant properties and polyphenol composition of aromatised green tea infusions

2012 ◽  
Vol 92 (11) ◽  
pp. 2244-2249 ◽  
Author(s):  
Anna Pȩkal ◽  
Paulina Dróżdż ◽  
Magdalena Biesaga ◽  
Krystyna Pyrzynska
Keyword(s):  
Green Tea ◽  
Antioxidant Properties ◽  
Tea Infusions

scholarly journals Influence of phenolic compounds on sensory parameters of tea infusions

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S195-S198
Author(s):  
P. Košulič ◽  
J. Pokorný ◽  
Z. Panovská
Keyword(s):  
Phenolic Compounds ◽  
Green Tea ◽  
Black Tea ◽  
Total Polyphenols ◽  
Iso Standards ◽  
Tea Infusions ◽  
Sensory Parameters

A set of 9 black teas and 10 green teas were analyzed. Sensory parameters of tea infusions were correlated with the content of total polyphenols (determined after Folin and Ciocalteu) and sensory parameters (determined after ISO standards). Total polyphenols affect both the astringency and the bitterness of green tea and black tea infusions. The relations are mainly semilogarithmic, but very close to linear. Sucrose decreased the astringency by 30–40%, and the bitterness was suppressed still more.

scholarly journals Formation of damascenone derived from glycosidically bound precursors in green tea infusions

2010 ◽  
Vol 123 (3) ◽  
pp. 601-606 ◽  
Author(s):  
Tomomi Kinoshita ◽  
Satoshi Hirata ◽  
Ziyin Yang ◽  
Susanne Baldermann ◽  
Emiko Kitayama ◽  
...  
Keyword(s):  
Green Tea ◽  
Tea Infusions

Determination of lemon and carbonate effects on caffeine content of various teas and investigation of daily caffeine intakes / Çeşitli çayların içerdikleri kafein miktarlarına limon ve karbonatın etkisi ve günlük alım miktarlarının incelenmesi

2016 ◽  
Vol 41 (5) ◽  
Author(s):  
Funda Demir ◽  
Azmi Seyhun Kıpçak ◽  
Özgül Dere Özdemir ◽  
Mehmet Burçin Pişkin ◽  
Emek Möröydor Derun
Keyword(s):  
Green Tea ◽  
Camellia Sinensis ◽  
Black Tea ◽  
Daily Maximum ◽  
Caffeine Content ◽  
Tea Infusions ◽  
Health Field

AbstractObjective: Tea (Camellia sinensis), has been used for health field in thousands of years. Caffeine is one of the key component in tea and investigation of caffeine is a popular working subject among the researches. The novelty of this study is not only the determination of the caffeine contents of the teas, but also how addition of lemon and carbonate effects the caffeine contents. Another aim of the study is the investigation of the daily caffeine intakes from teas.Methods: Tea infusions were prepared and caffeine contents were extracted by using chloroform and determined by UV-Vis Spectrophotometer. For lemon and carbonate addition experiments, lemon was added before the caffeine analysis and carbonate was added at the beginning.Results: Maximum caffeine contents from highest to lowest were seen in black, earl grey and green in classic teas; fennel, mint and sage in herbal teas; lemon, apple and rosehip in fruit teas. With lemon addition caffeine contents were increased except green tea and with carbonate addition caffeine contents were decreased except black and fennel tea. Daily caffeine intakes are found between 32.10% (green tea with carbonate) - 77.20% (black tea with lemon), 1.85% (sage tea with carbonate) - 4.05% (fennel tea with lemon) and 2.10% (rosehip with carbonate) - 4.00% (lemon tea with lemon) in classic, herbal and fruit teas, respectively.Conclusion: The significance of this study indicates that herbal and fruit teas contain caffeine, which is assumed zero in literature. The caffeine amount of herbal teas (20.79±0.36-30.68±0.63 ppm) were found barely higher than the fruit teas (22.87±0.54-28.54±0.75 ppm) but daily maximum caffeine intakes were found less than 5%. The daily maximum caffeine intakes were found in the teas as 525.36±2.84-20.79±0.36 ppm, where lemon addition increased to 617.90±3.54-22.97±0.58 ppm and carbonate addition decreased to 488.54±2.05-16.84±0.28 ppm.

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